Calipers



W. H. HARRIS.

CALIPERSI APPLlCATION FILED FEB. 18, I921.

Patented Aug. 23, 1921 A TTORNEYS STATES PATENT OFFICE.

WILLIAM HENRY HARRIS, OF LAURIUM, MICHIGAN.

CALIIEBS.

. To all whom it my concern:

Be it known that 1, WILLIAM H. Harms,

a citizen of the United States, and a resident of Laurium, in the county of Hou -hton and State of Michigan, have invente new and Improved Calipers, of which the following is a full, clear, and exact description.

7 so construct a mechanism of this character tion' thereof;

that it isespecially adapted to the caliper shown and described inmy previous patent above mentioned.

Vl ith the above and other objects in view, reference is had to the accompanying drawings, in which--- Figure 1 is a view in evelation of a pair of calipers constructed. in accordance with the present invention;

Fig. 2 is a detail sectional view of a por- Fig. 3 is horizontal sectional view taken on the IiIlBZS-S of Fig. 1.

Referring more particularly to the drawings the reference character 10 designates the legs of the caliper and said legs are of the usual curved form and taper to their free extremities. These legs have their corresponding ends secured together by means of a crown piece 11, in which the legs are piv-- otally mounted as indicated by the reference character 12. The crown piece 11 is pro vided with a centrally disposed opening 13, and rigidly secured in said opening in any desired manner is a centering rod 14, the upper end of which is provided with a suit-- able crating member in the form of a knob- 15. lower end with a bore 16 and mounted in said bore is a pointed member 17, the lower end of which is provided with a point 18 it being understood that the pointed member 1'? projects beyond the .end of the centering rod 14. This pointed member 17 is cut out as indicated by the reference character 19,

Specification of Letters Patent.

Application filed February 18, 1921. Serial No. 446,021.

his centering rod 14 is provided at its Patented Aug. 23, 1921.

and carried by the centering rod 14 and e11- gaging the cut-out portion 19 of the pointed member 17 is a threaded bolt or the like 20, which bolt serves the purpose of limiting the sliding movement of the pointed member 17 within the rod 14. The reference character 2l designates a coil spring which is positioned in the bore 16 oi the centering rod 14 and tends to project the pointed member forwardly at all times byreason of its engagement with the rear end thereof as indicated by the reference character 21'.

Mounted upon the centering rod 1 is a sliding block 22 and said block 22 is provided with extensions 23 in the form of sleeves, said block being provided with a central opening 2 l'through which the centering rod 14 slides. At opposite sides of the bloclrQQ ears are provided and pivotally secured in openings Q6 in said ears as by means of rivets or the like 27, are linhs 28, said links being pivotally connected to their respective legs of the caliper by means oi bolts or rivets 2th interposed between the crown piece 11 and the upper sleeve 23 of the sliding block 291 is compression when it is positioned on the centering rod 14. By this construction it will be seen that the helical spring 80 en erts a. constant force in a direction to move the sliding block 22 longitudinally of the centering rod 14, and through the medium of the links 28, normally tend to pull the free extremities 35 of the legs 10 toward each other. By this mechanism it is apparent that the free ends 35 of the legs 10 are at all times maintained in engagement with the work by means of the spring in stead of gripping the device to move the free ends of the legs 10 into contact with thework as is the common practice.

When it is desired to determine the center oi a body the caliper is passed across the end of the body with the extremities of the legs engaging the sides of the body, the spring 30 serving to maintain the extremities of the contact with the sides of the body. l l ith the parts in this position, the

point 1*? passes across the end taco oi the body to lllflltfi a marlin the point 18 serving; to scratch the body. The operation is then repeated by melting a mark at an angle to the former point so that a second line is formed which intersects the first-mentioned line. The intersection of these two lines constia a coil spring adapted to be placed under tutes the center of the end face of the body. It will be understood that owing to the resilient mounting of the jointed member 17,

i I the latter adjusts itself to the face, the center of which is being determined.

I claim: l. A device of the class described comprising legs, a member pivota lly connected to sald legs, a centering rod r1 'dlysecured to said member, a slide mova ly mounted on said rod, links operatively connecting said slide with said legs, and ajhelical spring interposed between said slide and the member to which the legs are pivotally connected.

2. A device of the class described compris-' block, and a helical spring surrounding the centering rod and inter osed between the crown plece and the sliding block whereby the sliding block is moved automatically longitudinally of the centering rod to cause an automatic contraction of the le 3. A device of the class describe comprising a crown piece,'a pair of legs pivotally carried by the crown piece, a centering rod rigidly carried by the crown piece and projecting between said legs, a slidin block carried by the centering rod, a helica spring surrounding the centering rod and interosed between the crown pieces and the slidlng block to move the sliding block longitudinally of the'centering rod, and means for causing a contraction of the le upon sliding movement of the sliding bloc under the influence of said coil s rin WILLIAM HEN Y I ARRIS 

